New approaches are urgently needed to improve agricultural production, given the steadily growing global population that is predicted to reach 6-9 billion persons by mid-century, the continual strain on existing and finite agricultural lands, and the recent diversion of valuable agricultural land from production of crops to production of biomass for fuels. Here we describe new approaches that may serve to generically increase agricultural production by stemming the adverse effects of microorganisms on plants.
Melander and coworkers recently reported a study wherein they identified novel synthetic compounds that inhibit biofilm formation (Huigens, R. W., III; Richards, J. J.; Parise, G.; Ballard, T. E.; Zeng, W.; Deora, R.; Melander, C. J. Am. Chem. Soc. 2007, 129, 6966-6967). Biofilms are communities of microorganisms (primarily bacteria but also can include archaea, protozoa, and algae) anchored to a surface (Molecular Ecology of Biofilms; McLean, J. C.; Decho, A. W., Eds, Horizon Scientific Press: Norfolk England, 2002.; see also “Biofilm” in Wikipedia). It is estimated that the majority of all bacteria are present in biofilms rather than in free-swimming (planktonic) form. The inspiration for the Melander paper stemmed in part from recognition that marine natural products that serve as antifouling agents or antifeedants function to inhibit biofilm formation. The marine organisms in particular are marine sponges, which have long been recognized as valuable sources of bioactive compounds (Thakur, N. L.; Muller, W. E. G. Curr. Sci. 2004, 86, 1506-1512). Moreover, the authors identified a common structural motif in a variety of such marine natural products, a 2-aminoimidazole, and hypothesized that the imidazole moiety, in conjunction with an annulated ring, constituted the core pharmacophore of the marine product. Synthetic analogues of this core unit proved to exhibit high activity in the inhibition of biofilm formation.
The five main crops on which modern societies depend most heavily include corn, cotton, rice, soybeans, and wheat. All of these crops are affected in a deleterious manner by biofilm formation. In addition, other valuable plants such as those producing fruits and vegetables are similarly affected. Plants grown for biomass stand to increase as a valuable crop, albeit not for food, and also can benefit from protection from biofilm formation. Forestry crops also suffer from biofilms.